conditions for life

Question 1

what does having high atmospheric pressure + suitable temperatures allow?

Answer 1

liquid water

Question 2

why is a magnetic field importent?

Answer 2

to deflect solar winds

Question 3

what does distance from the sun affect?

Answer 3

• the length of the year + seasonal change
• temperature
• light levels

Question 4

what would happen if the earth had a lower gravitational pull?

Answer 4

atmosphere would disperse +
gases would disperse

Question 5

would would happen if earth didn’t have an iron core?

Answer 5

no magnetic core -> ozone layer = destroyed + atmosphere no longer protected, no deflection of solar winds

Question 6

what does distance from the sun, the atmosphere and greenhouse gases control?

Answer 6

temperature range

Question 7

how does earth have an atmosphere?

Answer 7

big enough gravity + magnetic field

Question 8

what does the tilt of the earth affect?

Answer 8

seasons!

Question 9

what affects day + night?

Answer 9

earths spin

Question 10

why is liquid water important for life?

Answer 10

-temperature buffer (high heat capacity)
-solvent - aids substance uptake eg. nutrients

Question 11

why is having a suitable temperature range importent for life ?

Answer 11

enzyme activity:
temps too high = enzymes denature
temps to low = enzyme activity too low
+ allows existence of liquid water

Question 12

why is the atmosphere important for life?

Answer 12

-enough co2 for photosynthesis
-enough o2 for aerobic respiration
-enough nitrogen for proteins
-ozone absorbs harmful UV
-greenhouse gases - suitable temps

Question 13

why are season important for life?

Answer 13

reduce extreme temperatures

Question 14

why is visible light important for life?

Answer 14

• energy source for photosynthesis
  -sense of time
  -sense of periodicity
  -vision

Question 15

how did early photosynthetic organisms change the atmosphere?

Answer 15

decrease of co2 + increase in o2 through photosynthesis
formation of ozone

Question 16

describe how earths atmosphere changed over time

Answer 16

-volcanos released co2, ch4, h2s making the atmosphere
-co2 absorbed in oceans + rain
-co2 decreased + formation of limestone
-co2 stored in sediment
-development of photosynthetic organisms (bacteria) produced oxygen
-oxygen reacts with iron in water
-oxygen allows aerobic respiration
-oxygen forms ozone
-ozone absorbs + protects against UV from sun
-mammals + plants colonize the land
-co2 decrease further

Question 17

how do plants increase atmospheric humidity?

Answer 17

transpiration

Question 18

name 2 types of proxy data (for data on climate change)

Answer 18

-dendrochronology
-pollen analysis

Question 19

what is dendrochronology?

Answer 19

proxy data - trees growth rate changes in a predictable pattern throughout the year in response to seasonal climate

Question 20

what are some limitations of dendrochronology?

Answer 20

-not super reliable - other factors affect growth eg. water, light
-tree availability only in specific locations, not everywhere
-doesn’t go that far back in time

Question 21

what is pollen analysis?

Answer 21

proxy data - allows a scientist to determine what plants were living in a particular area at a particular time

Question 22

name 4 limitations of early methods of measuring earths past conditions

Answer 22

-lack of historical data
-limited reliability of proxy data (natural recorder, not direct evidence)
-limited coordination between researchers
-lack of equipment for accurate measurements
-inability to measure many factors
-lack of data collection in many areas